It has heretofore been proposed to provide a squeeze-type container package for dispensing viscous products, such as toothpaste, that includes a resilient self-closing valve mounted on a closure assembly at the container mouth. The valve is of resilient elastomeric composition, and includes a dispensing opening that is normally closed by internal resiliency of the valve material. When the flexible container is squeezed to dispense product, internal pressure forces the product through the valve opening. When the container is released, negative pressure within the container retracts the product at the container opening, so that the valve opening is closed both by the negative pressure of retracting product and internal resiliency of the valve material. In valves of this type of conventional design, it is typically necessary to cut the dispensing opening in the valve in a secondary operation after molding of the valve body.
It is a general object of the present invention to provide a self-closing valve of the described character, and a method of fabrication, in which the dispensing opening is fabricated in the valve during molding of the valve body in a unitary integrally molded construction, and thus does not require a secondary operation to form the dispensing opening. Another object of the present invention is to provide a valve and method of construction of the described character in which the valve cooperates with the closure when assembled to a squeeze-type dispensing package automatically to vent air into the package when the container body is released following a dispensing operation. Yet another of the present invention is to provide a self-closing valve, a method of fabrication, a valve and closure assembly, and a squeeze-type container package that achieve one or more of the foregoing objectives, and may be readily and inexpensively fabricated employing otherwise conventional technology.
A valve for a self-sealing dispensing closure in accordance with one aspect of the present invention takes the form of a one-piece construction of integrally molded elastic composition that has an annular base, an internal wall portion that extends radially and axially from the annular base, and a mouth portion that includes a slit oriented diametrically of the annular base. The wall portion of the valve is internally stressed for resiliently biasing the slit closed. A pair of lugs are provided on the wall portion of the valve diametrically opposed to each other and orthogonal to the slit opening on a side of the wall portion remote from the annular base, with the lugs being internally stressed for assisting the wall portion in resiliently biasing the slit opening to a closed position. Ribs on the mouth portion of the valve extend along each side of the slit opening, and are internally stressed for maintaining diametric orientation of the slit opening.
The valve is mounted in accordance with another aspect of the invention in a self-sealing closure assembly that includes a plastic closure shell having a central opening at which the slit opening of the valve is disposed. In accordance with a third aspect of the invention, the closure assembly is mounted on a resilient container body. The valve has a peripheral rib that extends radially outwardly from the annular base, which is captured by a basket within the closure against the base wall of the closure. A peripheral lip extends radially outwardly from the rib, and normally engages an annular internal rib on the base wall of the closure. When the resilient container is released following dispensing of product, negative pressure within the container pulls the lip from the annular rib on the closure, and the internal volume of the container is vented to atmosphere around the lip through a series of channels between the valve rib and the closure base, and through an opening in the basket that captures the valve against the closure base.